M-OS is single task operating system for Raspberry Pi Zero.
Features
- Command line interface
- Simple file system
- Text editor
- BASIC interpreter
Command line interface
MOS don't using graphic or USB keyboard, all communication is over serial (UART). You need to connect pin 14 and 15 to USB over UART module and operate with putty. Also you can power RPi with UART module over pin 5V just like on circuit diagram. Command line interface supports few commands: basic (for start BASIC interpreter), edit (for start text editor), ls (for print all files in memory), and other commands for manipulate with files. Type 'help' to view all supported commands.
File system
MOS is using simple file system on external flash memory. Flash memory is splitted into 16 blocks of 8 kB, so every file can be max 8 kB and it can contain up to 16 files with memory capacity 128 kB. File system is not supporting directories, only files.
Text editor
You can run simple text editor by typing 'edit' to create or modify text file. Editor supports only four commands: move cursor up (Ctrl+U), move cursor down (Ctrl+D), save file to flash memory (Ctrl+S) and exit from editor (ESC).
BASIC interpreter
This simple version of BASIC interpreter allows you to create and run your programs. It supports over 20 commands for input/output, read/write file, control GPIO pins and others. To view all supported commands and grammar, type 'basic grammar'. For example: blink LED program
Circuit:
- Raspberry Pi Zero
- Serial: CP2102 USB 2.0 to TTL UART module 6 pin serial converter
- Flash Memory: 25LC1024 (128 kB SPI memory)
